River Bank System

A simple command-line interface (CLI) banking application written in Python.

Features

• User registration and login
• Deposit, withdraw, and transfer funds between current and savings accounts
• View transaction history
• Secure password hashing with bcrypt
• Configuration via environment variables

---

Setup

1. Clone the repository:

   git clone https://github.com/H41L33/t_level_dsd_river_bank_system
   cd river_bank_system

2. Install Poetry: If you don't have Poetry installed, follow the instructions on the official Poetry website.

3. Install dependencies: Poetry will create a virtual environment automatically and install the dependencies listed in the pyproject.toml file.

   poetry install

4. Configure environment variables:

   • Copy the .env.example file to .env:

     cp .env.example .env

   • Edit the .env file with your desired settings.

---

Usage

Run the main application using Poetry's run command. This ensures the script executes within the correct virtual environment managed by Poetry.

poetry run python -m river_bank_system.main

Tutorial

🌊 How it Works: Data Flow

The application is designed to be a loop, continuously prompting the user for input until they choose to exit. Here’s a breakdown of how data moves through the system with the new structure.

1. Initial Startup

• The program starts by running main.py.
• The main() function immediately calls menus.program_start(), which clears the screen and displays the first choice: Login, Register, or Quit.

2. User Creation

• If you choose to register, you'll be guided by the create_user_prompt() function in menus.py.
• This function collects your desired username, display_name, and password.
• Your password is then sent to crypto.hash_bcrypt() to be securely hashed.
• Finally, this information is passed to users.UsersDB().create_new_user(), which inserts a new record into the tbl_accounts table in your SQLite database.

3. User Login

• If you opt to log in, the login_prompt() function in menus.py will ask for your username and password.
• The username is used to fetch the stored password hash from the database via users.UsersDB().get_password_hash().
• The plain-text password you entered and the stored hash are then passed to auth.check_password() to see if they match. bcrypt handles this comparison securely without ever exposing the original password.

4. Account Dashboard & Actions

• Once logged in, the home_page() function in main.py takes over.

• It uses menus.account_dashboard() to display your account balances and the available actions: Deposit, Withdraw, Transfer, View Transactions, and Logout. Your balance information is fetched from the database using functions within the users.UsersDB class.

• When you select a financial action (like Deposit), main.py creates an actions.Actions(username) object. This object manages the two-step process for every transaction:

  1. Update Balance: The Actions class first calls a method from the users.UsersDB class (e.g., add_current_balance) to update your balance in the tbl_accounts table.
  2. Log Transaction: Immediately after, it calls transactions.TransactionsDB().log_transaction() to create a permanent record of the event in the tbl_transactions table.

• If you choose to view your history, main.py calls transactions.TransactionsDB().get_transactions() to retrieve and display the recent records.

---

🛠️ Key Libraries

To enhance the functionality and security of this command-line application, a few key external libraries were chosen:

• Click: This library is used to create a more user-friendly and robust command-line interface (CLI). Instead of using Python's built-in input(), Click provides functions for styled output (like colors), clearing the screen, and creating clean, validated prompts. This improves the overall user experience when interacting with the bank system in the terminal.

• Bcrypt: Security is paramount when dealing with user credentials. The bcrypt library is a trusted and secure way to handle password hashing. When a user creates a password, it is not stored in plain text. Instead, it is run through a hashing algorithm to create a unique, fixed-length "hash." When the user logs in, the password they enter is hashed again and compared to the stored hash. This ensures that even if the database were compromised, the actual passwords would remain protected.